How to compare between two images?

[BlurayHD]

Hi gys, I currently encoding from HD to DVD and trying between two programs (I need it), but I just dont know what result is better, so, I so in several sites some posted images comparison and that is just that I need, but I dont know how to do that?

I mean, an example, I have two DVD movies that was previously encoding but I so need to compare that movies taking some picture from them so I´ll can see the result from both

Thank you in advance!!

[SaurusX]

Alt+PrintScreen and paste into MS Paint? If I'm only looking at an individual frame then that's how I do all of my quick comparisons. Then it's just ctrl+z and ctrl+y to flip back and forth.

[_Al_]

Avisynth (using with AvsPmode) or Vapoursynth and compare particular video frames directly

[jagabo]

Open the videos using two instances of VirtualDub FilterMod. Step through them and compare.

[raffriff42]

Using any image editor with layers, put image B on top of image A and toggle B's layer off and on. Or (for a different, more technical comparison) set B's merge mode to "difference."

Using AviSynth, use Interleave(A, B). This is only useful in frame jog mode! Or use Subtract(A, B)

[poisondeathray]

Using any image editor with layers, put image B on top of image A and toggle B's layer off and on.

And that's the *best* feature of avspmod. Tabs! .

You can load different versions in different tabs, and the number keys to toggle. It's automatically aligned if they are the same video (same dimensions, framecount) , and you can seek to another frame (e.g. frame 3753), and all tab instances are aligned on that same frame so you can toggle between them easily. If you want to save a screenshot, you can do that directly from avspmod too

[jagabo]

When I'm doing serious comparisons of encoding settings I use three videos, the original and the two encoded videos, interleaved as original, encoded 1, encoded 2, original. This makes it easy to switch back and forth directly between the original and encoded 1, encoded 1 and encoded 2, and encoded 2 and the original.

original = WhateverSource("original.ext")
encoded1 = WhateverSource("encoded1.ext")
encoded2 = WhateverSource("encoded2.ext")

Interleave (original, encoded1, encoded2, original)

Open that in an editor like VirtualDub with frame by frame advance/reverse (right/left arrow keys). This way it's much easier to tell which is more true to the source, as well as seeing differences between the two encoded videos. I also use Microsoft's screen magnifier to zoom into parts of the picture of interest.

And, of course, not all issues show up when examining still frames like this; some problems need to be seen at normal playback speed. You can use StackHorizontal() or StackVertical() to play back multiple files simultaneously.

original = WhateverSource("original.ext")
encoded1 = WhateverSource("encoded1.ext")
encoded2 = WhateverSource("encoded2.ext")

StackHorizontal(original, encoded1, encoded2)

That doesn't work well if the resulting frame is too wide to fit on the screen. When that happens I'll crop the videos before stacking.